Common 'Cold Sore' Virus May Double the Risk of Dementia

Researchers from Uppsala University in Sweden found that people living with herpes simplex virus are twice as likely to develop dementia.

Herpes simplex viruses (HSV), including HSV type 1 (HSV-1) and HSV type 2 (HSV-2), are common among the general population. According to the National Institute of Allergy and Infectious Diseases, in the United States, up to 80% of people between the ages of 14 and 49 years live with HSV-1, and over 10% live with HSV-2.

HSV-1, or oral herpes, primarily causes painful blisters around the mouth, while HSV-2, or genital herpes, usually shows up as blisters around the genitals.

HSV is highly contagious and transmitted through close contact activities, such as kissing or sex.


Although anti-viral treatments can reduce the number of outbreaks a person experiences, the condition is considered lifelong. Moreover, previous research has found links between HSV and Alzheimer's disease.

Now, research published on February 13 in the Journal of Alzheimer's Disease found more evidence linking HSV to a higher risk of dementia. The findings showed that people who acquired HSV at some point in their lives may have double the risk of dementia compared to those without the condition.

The researchers recruited 1,002 70-year-old participants who did not have dementia and followed them for 15 years. The team analyzed the participants' serum samples to determine the levels of HSV antibodies in their blood. The presence of these antibodies in the blood indicates the person has the virus in their system.

They also collected data about the participants' diagnoses and prescription medications from medical records.

After the study concluded, the team found that participants with HSV antibodies in their blood had more than double the risk of dementia. However, in contrast to previous studies, they did not observe a significant association between HSV and Alzheimer's disease.

"It is exciting that the results confirm previous studies. More and more evidence is emerging from studies that, like our findings, point to the herpes simplex virus as a risk factor for dementia," first author Erika Vestin, a medical student at Uppsala University, explains in a press release. "The results may drive dementia research further towards treating the illness at an early stage using common anti-herpes virus drugs, or preventing the disease before it occurs."

The study's authors say previous research suggests that treating HSV with antiviral medications may help reduce dementia risks. One such study found that anti-herpesvirus treatment could lower the risks by 70%.

However, other research found that these treatments did not reduce the risk of cognitive impairment in people with HSV.


Currently, no vaccines are approved to prevent the disease. However, several herpes vaccine candidates are under investigation.

To help understand HSV better, the National Institutes of Health (NIH) released the Strategic Plan for Herpes Simplex Virus Research in 2023. This plan outlines strategies to increase knowledge about HSV, improve diagnosis, find more effective treatments, and advance research on disease prevention.


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